Early visual experience influences behavioral lateralization in the guppy

Individual differences in lateralization of cognitive functions characterize both humans and non-human species. Genetic factors can account for only a fraction of the variance observed and the source of individual variation in laterality remains in large part elusive. Various environmental factors have been suggested to modulate the development of lateralization, including asymmetrical stimulation of the sensory system during ontogeny. In this study, we raised newborn guppies in an asymmetric environment to test the hypothesis that early left–right asymmetries in visual input may affect the development of cerebral asymmetries. Each fish was raised in an impoverished environment but could voluntarily observe a complex scene in a nearby compartment containing a group of conspecifics. Using asymmetric structures, we allowed some subjects to observe the complex scene with the right eye, others with the left eye, and control fish with both eyes. Among asymmetrically stimulated fish, the mirror test revealed eye dominance congruent with the direction of asymmetric stimulation, while controls showed no left–right laterality bias. Interestingly, asymmetric exposure to social stimuli also affected another aspect of visual lateralization—eye preference for scrutinizing a potential predator—but did not influence a measure of motor asymmetry. As the natural environment of guppies is fundamentally asymmetrical, we suggest that unequal left–right stimulation is a common occurrence in developing guppies and may represent a primary source of individual variation in lateralization as well as an efficient mechanism for producing laterality phenotypes that are adapted to local environmental conditions.     

Male and female guppies differ in speed but not in accuracy in visual discrimination learning

In many species, males and females have different reproductive roles and/or differ in their ecological niche. Since in these cases the two sexes often face different cognitive challenges, selection may promote some degree of cognitive differentiation, an issue that has received relatively little attention so far. We investigated the existence of sex differences in visual discrimination learning in the guppy, Poecilia reticulata, a fish species in which females show complex mate choice based on male colour pattern. We tested males and females for their ability to learn a discrimination between two different shapes (experiment 1) and between two identical figures with a different orientation (experiment 2). In experiment 3, guppies were required to select an object of the odd colour in a group of five objects. Colours changed daily, and therefore, the solution for this task was facilitated by concept learning. We found males’ and females’ accuracy practically overlapped in the three experiments, suggesting that the two sexes have similar discrimination learning abilities. Yet, males showed faster decision time than females without any evident speed–accuracy trade-off. This result indicates the existence of consistent between-sex differences in decision speed perhaps due to impulsivity rather than speed in information processing. Our results align with previous literature, indicating that sex differences in cognitive abilities are the exception rather than the rule, while sex differences in cognitive style, i.e. the way in which an individual faces a cognitive task, are much more common.     

Negative priming 1985 to 2015: a measure of inhibition,the emergence of alternative accounts,and the multiple process challenge

In this article, three generations of authors describe the background to the original article; the subsequent emergence of vigorous debates concerning what negative priming actually reflects, where radically different accounts based on memory retrieval were proposed; and a re-casting of the conceptual issues underlying studies of negative priming. What started as a simple observation (slowed reaction times) and mechanism (distractor inhibition) appears now to be best explained by a multiple mechanism account involving both episodic binding and retrieval processes as well as an inhibitory process. Emerging evidence from converging techniques such as functional magnetic resonance imaging (fMRI), and especially electroencephalography (EEG), is beginning to identify these different processes. The past 30 years of negative priming experiments has revealed the dynamic and complex cognitive processes that mediate what appear to be apparently simple behavioural effects.     

Economic Impact of Third-Wave Cognitive Behavioral Therapies: A Systematic Review and Quality Assessment of Economic Evaluations in Randomized Controlled Trials

The term third-wave cognitive behavioral therapy (CBT) encompasses new forms of CBT that both extend and innovate within CBT. Most third-wave therapies have been subject to randomized controlled trials (RCTs) focused on clinical effectiveness; however, the number and quality of economic evaluations in these RCTs has been unknown and may be few. Evidence about efficiency of these therapies may help support decisions on efficient allocation of resources in health policies. The main aim of this study was to systematically review the economic impact of third-wave therapies in the treatment of patients with physical or mental conditions. We conducted a systematic literature search in PubMed, PsycINFO, EMBASE, and CINALH to identify economic evaluations of third-wave therapies. Quality and Risk of Bias (RoB) assessment of economic evaluations was also made using the Drummond 35-item checklist and the Cochrane Collaboration’s tool for assessing risk of bias, respectively. Eleven RCTs were included in this systematic review. Mindfulness-Based Cognitive Therapy (MBCT), Mindfulness-Based Stress Reduction (MBSR), Acceptance and Commitment Therapy (ACT), Dialectical Behavior Therapy (DBT), and extended Behaviour Activation (eBA) showed acceptable cost-effectiveness and cost-utility ratios. No study employed a time horizon of more than 3 years. Quality and RoB assessments highlight some limitations that temper the findings. There is some evidence that MBCT, MBSR, ACT, DBT, and eBA are efficient from a societal or a third-party payer perspective. No economic analysis was found for many third-wave therapies. Therefore, more economic evaluations with high methodological quality are needed.     

Short-term consolidation of individual identities leads to Lag-1 sparing

A rapid serial visual presentation (RSVP) technique was used to investigate the role of the nature of processing carried out on targets in the Lag-1 sparing phenomenon. Lag-1 sparing refers to a higher accuracy in the task associated with the 2nd target when the 2 targets are immediately successive in the RSVP stream relative to when there are 1 or 2 intervening items between the targets. In 5 experiments, 0, 1, or 2 digits were embedded with equal probability in RSVP streams of letter distractors. In 4 of the experiments, subjects identified the digits in some blocks of trials, and they counted the number of presented digits in other blocks. In a 5th experiment, the counting task was replaced with a digit-sum task. The most interesting results were those from trials with 2 digits. Lag-1 sparing was always evident when the task involved the explicit identification of the digits. In addition, Lag-1 sparing was evident when subjects were required to sum 2 digits or to count digits of a prespecified parity subclass (e.g., count only even digits). In striking contrast, Lag-1 sparing was absent when subjects were required to count the digits independent of their parity subclass. These results suggest that the occurrence of Lag-1 sparing depends on the type of mental representation that must be generated on the basis of target information.     

Multisensory-mediated auditory localization

Multisensory integration is a powerful mechanism for maximizing sensitivity to sensory events. We examined its effects on auditory localization in healthy human subjects. The specific objective was to test whether the relative intensity and location of a seemingly irrelevant visual stimulus would influence auditory localization in accordance with the inverse effectiveness and spatial rules of multisensory integration that have been developed from neurophysiological studies with animals [Stein and Meredith, 1993 The Merging of the Senses (Cambridge, MA: MIT Press)]. Subjects were asked to localize a sound in one condition in which a neutral visual stimulus was either above threshold (supra-threshold) or at threshold. In both cases the spatial disparity of the visual and auditory stimuli was systematically varied. The results reveal that stimulus salience is a critical factor in determining the effect of a neutral visual cue on auditory localization. Visual bias and, hence, perceptual translocation of the auditory stimulus appeared when the visual stimulus was supra-threshold, regardless of its location. However, this was not the case when the visual stimulus was at threshold. In this case, the influence of the visual cue was apparent only when the two cues were spatially coincident and resulted in an enhancement of stimulus localization. These data suggest that the brain uses multiple strategies to integrate multisensory information.     

Quantity discrimination in female mosquitofish

The ability in animals to count and represent different numbers of objects has received a great deal of attention in the past few decades. Cumulative evidence from comparative studies on number discriminations report obvious analogies among human babies, non-human primates and birds and are consistent with the hypothesis of two distinct and widespread mechanisms, one for counting small numbers (<4) precisely, and one for quantifying large numbers approximately. We investigated the ability to discriminate among different numerosities, in a distantly related species, the mosquitofish, by using the spontaneous choice of a gravid female to join large groups of females as protection from a sexually harassing male. In one experiment, we found that females were able to discriminate between two shoals with a 1:2 numerosity ratio (2 vs. 4, 4 vs. 8 and 8 vs. 16 fish) but failed to discriminate a 2:3 ratio (8 vs. 12 fish). In the second experiment, we studied the ability to discriminate between shoals that differed by one element; females were able to select the larger shoal when the paired numbers were 2 vs. 3 or 3 vs. 4 but not 4 vs. 5 or 5 vs. 6. Our study indicates that numerical abilities in fish are comparable with those of other non-verbal creatures studied; results are in agreement with the hypothesis of the existence of two distinct systems for quantity discrimination in vertebrates.     

Health literacy, health inequality and a just healthcare system

Limited health literacy is a pervasive and independent risk factor for poor health outcomes. Despite decades of reports exhibiting that the healthcare system is overly complex, unneeded complexity remains commonplace and endangers the lives of patients, especially those with limited health literacy. In this article, we define health literacy and describe the empirical evidence associating health literacy and poor health outcomes. We recast the issue of poor health literacy from within the ethical perspective of the least well-off and argue that poor health outcomes deriving from limited health literacy ought to be understood as a fundamental injustice of the healthcare system. We offer three proposals that attempt to rectify this injustice, including: universal precautions that presume limited health literacy for all healthcare users; expanded use of technology supported communication; and clinical incentives that account for limited health literacy.     

Crime behaviours and distance travelled in homicides and rapes

We explored (1) distances between home and offence in homicides and rapes; (2) whether these distances differed from each other; and (3) whether offence features were associated with distances. The sample consisted of solved homicides (N = 40) and rapes (N = 37) from Finland with co‐ordinates for offence and offender home locations and information on crime features. Empirical models of incident density as a function of distance were estimated using CrimeStat III (Levine, 2004). Most of the distances were short displaying distance decay. Homicide median distance was 0.85km (Inter Quartile Range (IQR) = 0.13–7.69km) and rape median distance 2.44km (IQR = 0.83–6.96km) from perpetrators' home location. These distances differed significantly (Mann‐Whitney U = 543.0, p < 0.045). It was possible to identify crime features that were correlated with distances in both offence types. Spatial Behaviour Indices combining crime feature information correlated r_s = 0.77 with distance in homicides and r_s = 0.72 in rapes. Identifying theoretical constructs for understanding links between different crime features instead of looking at them in isolation is important. Copyright © 2007 John Wiley & Sons, Ltd.     

Perceptual and attentional factors in encoding irrelevant spatial information

Numerous studies found superior performance when the irrelevant location of a stimulus and response location were corresponding than when they were not corresponding (Simon effect), suggesting that stimulus location is processed in an obligatory manner. The present study compared Simon effects from the location of a relevant (i.e., to-be-attended) object to those from the location of an irrelevant (i.e., to-be-ignored) object. In four experiments, participants were presented with a rectangular frame and a square, with the relevant object in green or red color and the irrelevant object in gray or white color. Participants’ task was to respond with a lateral keypress to the color of the relevant object, and we varied spatial correspondence between the location of the relevant or the irrelevant object and the response, respectively. Results consistently showed larger Simon effects from the location of the relevant than from the irrelevant object, even when the irrelevant object was made very salient. These results suggest that location processing is largely confined to relevant (i.e., attended) objects, stressing the role of attention shifts for location encoding.